Plate inking device and method



March 21, 1939. v SHAW 2,151,411

PLATE INKING DEVICE AND METHOD Filed Feb. 24, 1936 INVENTOR.

ATTORNEYS Patented Mar. 21, 1939 PATENT OFFICE PLATE INKING DEVICE AND METHOD Charles P. Shaw, Detroit, Mich, assignor to DetroitMoulding Corporation, Detroit, Mich.

Application February 24, 1936, Serial No. 65,244

6 Claims.-

This invention relates to improvements in plate inking devices and method.

The main objects of this invention are First, to provide a method and device for inking relief or letterpress printing plates for reproducing graining effects.

Second, to provide a device of the type described, which eliminates the necessity for the numerous conventional transfer and vibrating rollers in such inking mechanisms.

Third, to provide a device of the type described which insures the delivery of a regulable and at all times uniform supply of ink to the printing plate.

Fourth, to provide a device of the type described which is simple and compact in its parts and operated with facility.

Fifth, to provide a device which will enable surface printing of fine work such as wood grain Work.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is: defined in the claims.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a fragmentary perspective view illustrating the inking device of my invention.

Fig. 2 is a fragmentary side elevational View in section, illustrating the relation of the parts.

Fig. 3 is a fragmentary top plan view illustrating the details of my invention.

Fig. 4 is a greatly enlarged sectional view of a portion of my supply roller, illustrating the roughened or pitted surface thereof.

It has heretofore been necessary to resortto the use of intaglio plates for the successful reproduction of wood grain effects by means of a printing operation, inasmuch as in surface or relief printing difiiculty has been experienced in getting sufficient ink and ink of the right consistency on the surface portions of the plate. It has been found that when conventional letterpress machines have been employed fairly good results at the beginning of the printing operation have been achieved, but that the quality'of the printing deteriorated later on, apparently due to the excessive working of the ink accompanying its transfer from the fountain through the various roll couples, vibrating rolls, etc. of the conventional press. In my Patent No. 1,989,250 of J anuary 29, 1935, I disclose and claim an ink which I have found to be eminently suitable for use in producing graining effects by relief offset printing as contemplated here. The ink is characterof to a great extent and it is likewise difficult to transfer an adequate quantity of ink in a uniform layer to the printing plate.

Applicant has solved the above difficulties in an exceedingly simple yet effective manner by replacing the numerous transfer and vibrating rollers with a single roller, the surface of which roller or cylinder is roughened to provide pits or pockets of exceedingly small size thereon. This roller is associated with a resilient plate inking or form roller, being in rolling contact with the same, and is likewise associated with a regulable scraper blade which in one simple and practical embodiment forms a trough in conjunction with the pitted roller adapted to receive printing ink. Details of the invention will be more specifically referred to in the disclosure to follow.

Referringto the drawing, reference numeral 1 indicates a flat surface printing plate suitably mounted on a base 2 which is placed on a bed 3 having a toothed rack 4 at either side thereof.

'Inking means are provided to supply ink to the surface of the plate referred to and the inking means may beeither manually or automatically actuated. In the embodiment illustrated, I

provide a carriage generally indicated by the 1 reference numeral 5, comprising a pair of side members 6 arranged in parallel relation at opposite sides of the bed and secured and spaced by tie rods 1. An operating handle 8 is secured to the side members and provides means whereby the carriage may be translated with respect to the plate I.

The side members 6 are slotted at the side thereof opposite the handle to provide a bearing slot 9 receiving a bearing block H) which is adjustable by means of an adjusting screw H threaded in a cap plate 12 and received in the bearing block [0. The shaft 13 of a suitable form inking roller [4 of rubber, leather, composition or other material is journaled in the bearing blocks, and at either end thereof the shaft is provided with pinions I 5 in mesh with the spaced racks 4 on the bed.

Rotatably journaled in the side members 6 above and to the rear of roller [4 is a further roller l 6 which may be designated a supply roller. The roller l 6 is removably trunnioned in the side members 6, being restrained by a cap plate l1, and gears 28 are mounted on the shaft of the roller is to mesh with pinions l5. The entire surface of the supply roller I6 is finely granular or minutely pitted or roughened to provide innumerable minute closely associated cavities or depressions of the nature illustrated in Fig. 4.

A transverse scraper blade [8 is secured at one side to a rod l9 extending transversely of the carriage, the blade being adjustably urged toward the roller l6 by a plurality of screws 20 threaded through a transverse rod 2| and having knurled heads 22.

By the above construction, a trough 23 is formed between the scraper l8 and the surface of supply roll Hi. The minute pits or cavities 24 on the surface of the supply. roll are effective to scoop up a quantity of ink from the trough, while the raised portions also receive a layer of ink the thickness of which is determined by the position of the scraper IS with respect to the supply roller. The charge of ink carried by the supply roller is then imparted to the yielding surface of the plate inking roller M. It should be borne in mind that the pits are of very small width and depth, hence a layer of ink is transferred to roller I4, which is substantially uniform in thickness. The pits serve the function of enabling a charge of ink to be placed on the roller I4 such as could not be transferred if both rollers had a smooth periphery. The inequalities of thickness in the layer of ink on the roll M are eliminated by the working action of the roll l6 against the roll M; The ink is transferred to the printing plate by the rolling of the roller l4 thereover, retaining all of its original consistency while at the same time an adequate thickness is imparted to the upper surface of the plate.

- Extending parallel with the racks 4 on the bed 3, I dispose a pair of rods 25 which function as tracks upon which grooved rollers 26 travel. The rollers are mounted on studs 21 extending inwardly of the side members 6. The tracks: and

rollers guide the carriage in its motion and prevent it from becoming askew, with resultant slurring of the ink coat in a manner which will be appreciated.

From the foregoing description, it will beclear that I have provided an apparatus capable of supplying a uniform film of ink of substantial thickness on the printing surface or cameo portions of an engraved plate. I have eliminated the necessity and desirability of a plurality of transfer rolls and also vibrating rolls for the purpose of accomplishing uniform coating of the plate. By so doing, I have obviated the very undesirable diminution of consistency of the inkdue to those rollers, with the result that after one passage of my inking apparatus across the plate to be inked a uniform coating of ink of even consist-v ency is deposited.

Bythe construction of my invention, I have greatly simplified the mechanism necessary to ink a surface printing plate and have also made it possible to do surface printing on fine work such as grain work, whereas previously satisfactory results have not been obtainable.

I have shown and described my apparatus as applied to the inking of a flat plate, yet it will be apparent to those skilled in the .art that the inventive principles of my invention are applicable and the specific structure may be readily modified to be applicable to inking operations of Varying natures such as rotary processes wherein a curved plate is inked. By the use of a plurality of knurled adjustingscrews, I make possible minute adjustments in the quantity of ink desired to be delivered to any particular portion of the plate, thus further materially contributing to the attainment of fine graining effects by the use of surface printing plates;

claim as new and desire to secure by Letters Patcut, is:

1. In inking mechanism of the type described for inking'a relief or surface printing plate, a carriage adapted to be translated past a printing plate to be inked, a plate inking roller journaled in said carriage for rolling contact with said plate, a supply roller journaled in said carriage in rolling contact with said plate inking roller, the surface of said supply roller being minutely grained, an adjustable scraper coacting with said supply roller to regulate the thickness of a layer of ink thereon, said supply roller transferring to said inking roller a uniform film of ink above the surface of the supply roller, augmented by ink in the minute grainings thereof, and means for translating the carriage past the plate to be inked to transfer ink directly thereto from said plate inking roll without further working of the ink.

2. In inking mechanism for uniformly inking the printing surface of a relief printing plate, a frame, a pair of rollers journaled in said frame in continuous rolling contact with one another, means for supplying ink to one of said rollers, the surface of said one of said rollers being minutely roughened or pitted, the other roller being mounted for direct rolling contact with the plate to be inked to transfer ink thereto without further working of the ink, and means for governing the thickness of the layerof ink on said roughened roller, to provide a uniform film of ink on the surface of the roughened roller augmented by ink in the pits thereof. a

3. In inking mechanism for uniformly inking the printing surface of arelief printing plate, a frame, a pair of rollers journaled in said frame in rolling contact with one another, means for supplying ink to one of said rollers, the'surface of said one of said rollers being minutely roughened or pitted, means for directly contacting the other roller with the plate to be inked after receiving ink from said pitted roller and without further working of the ink, and means for governing the thickness of the layer of ink on said roughened roller, said roughened roller transferring to the other roller a layer of ink of uniform thickness above the raised portions of said surface augmented by'the ink in the depressed or pitted portions thereof. 7 V

4. An inking mechanism for inking relief printing surfaces comprising an ink supply memberi for continuous rolling contact with said roughened surface and for direct contact with a print ing plate having a relief printing surface to be inked without further working of the ink on the inking roller.

5. In a device of the type described, a relief printing surface to be inked, ink supplying means, means receiving a coating of ink from said means, and having a granular minutely-roughened ink carrying surface, and means having rolling contact with said receiving means and said relief printing surface to be inked for transferring ink from said roughened ink carrying surface to the surface to be inked, said receiving means carrying and transferring to said transferring means a layer of ink of uniform thickness above the raised portions of said carrying surface, said layer being augmented by the ink in the depressed portions of said carrying surface, and means for controlling the thickness of sad layer.

6. The method of inking a relief printing surface for producing graining effects, comprising picking up from a supply of ink a film of ink which is generally uniform in thickness and augmented at a multiplicity of points by minute quantities of ink, regulating the thickness of said film, transferring the film augmented by the minute quantities directly to an ink applying member, and transferring the ink from said applying member to the relief surface to be inked without further working of the ink.

CHARLES P. SHAW. 

